Iran has a large underground Christian popylation.
I hope it’s not going to be like 1989 China where protest was encouraged and then we did nothing when the government cracked down on the protestors. The initial message if that’s going to be the case is, “don’t expect help from here, this is your problem to solve.” Of course Iran cannot threaten the U.S. in ways that China could, so perhaps there will be an intervention in large-scale suppression of protests. I would not count on it though.